feat(ticket): make it safe to render leaderboard tickets

[wescopeland]

Stacked on #4910.

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This PR makes it safe to render leaderboard tickets in the site front-end. Explicit leaderboard ticket creation is still unsupported.

How to test this PR

-- manually create a leaderboard ticket
INSERT INTO
	tickets (ticketable_type, ticketable_id, ticketable_author_id, type, state, body, hardcore, reporter_id, created_at, updated_at)
VALUES
	('leaderboard', 104370, 38243, 'did_not_submit', 'open', 'aaaa bbbb cccc dddd eeee ffff gggg hhhh', 1, 500838, NOW(), NOW());

There are three surfaces to try out:

• http://localhost:64000/game/1/tickets?filter%5Bstatus%5D=unresolved
• http://localhost:64000/ticket/111009 (replace this with your new ticket ID)
• On any forum post, [ticket=ID].

There is still quite a bit left to do in subsequent PRs, so I wouldn't necessarily treat any visible UI/UX at the moment as gospel.